package com.xiangxiao.rpan.file.config;

import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
import com.netflix.hystrix.HystrixThreadPoolKey;
import com.netflix.hystrix.HystrixThreadPoolProperties;
import com.netflix.hystrix.strategy.HystrixPlugins;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariable;
import com.netflix.hystrix.strategy.concurrency.HystrixRequestVariableLifecycle;
import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier;
import com.netflix.hystrix.strategy.executionhook.HystrixCommandExecutionHook;
import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesStrategy;
import com.netflix.hystrix.strategy.properties.HystrixProperty;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
/**
 * @auther xiangxiao
 * @email 573768011@qq.com
 * @data 2024/3/18 13:59
 */
@Slf4j
@Component
public class RequestAttributeHystrixConcurrencyStrategy extends HystrixConcurrencyStrategy {
  private HystrixConcurrencyStrategy delegate;

  public RequestAttributeHystrixConcurrencyStrategy() {
    try {
      log.info("加载RequestAttributeHystrixConcurrencyStrategy");
      this.delegate = HystrixPlugins.getInstance().getConcurrencyStrategy();
      if (this.delegate instanceof RequestAttributeHystrixConcurrencyStrategy) {
        // Welcome to singleton hell...
        return;
      }
      HystrixCommandExecutionHook commandExecutionHook = HystrixPlugins
          .getInstance().getCommandExecutionHook();
      HystrixEventNotifier eventNotifier = HystrixPlugins.getInstance()
          .getEventNotifier();
      HystrixMetricsPublisher metricsPublisher = HystrixPlugins.getInstance()
          .getMetricsPublisher();
      HystrixPropertiesStrategy propertiesStrategy = HystrixPlugins.getInstance()
          .getPropertiesStrategy();
      this.logCurrentStateOfHystrixPlugins(eventNotifier, metricsPublisher,
          propertiesStrategy);
      HystrixPlugins.reset();
      HystrixPlugins.getInstance().registerConcurrencyStrategy(this);
      HystrixPlugins.getInstance()
          .registerCommandExecutionHook(commandExecutionHook);
      HystrixPlugins.getInstance().registerEventNotifier(eventNotifier);
      HystrixPlugins.getInstance().registerMetricsPublisher(metricsPublisher);
      HystrixPlugins.getInstance().registerPropertiesStrategy(propertiesStrategy);
    }
    catch (Exception e) {
      log.error("Failed to register Sleuth Hystrix Concurrency Strategy", e);
    }
  }

  private void logCurrentStateOfHystrixPlugins(HystrixEventNotifier eventNotifier,
                                               HystrixMetricsPublisher metricsPublisher,
                                               HystrixPropertiesStrategy propertiesStrategy) {
    if (log.isDebugEnabled()) {
      log.debug("Current Hystrix plugins configuration is ["
          + "concurrencyStrategy [" + this.delegate + "]," + "eventNotifier ["
          + eventNotifier + "]," + "metricPublisher [" + metricsPublisher + "],"
          + "propertiesStrategy [" + propertiesStrategy + "]," + "]");
      log.debug("Registering Sleuth Hystrix Concurrency Strategy.");
    }
  }

  @Override
  public <T> Callable<T> wrapCallable(Callable<T> callable) {
    RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
    return new WrappedCallable<>(callable, requestAttributes);
  }

  @Override
  public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                          HystrixProperty<Integer> corePoolSize,
                                          HystrixProperty<Integer> maximumPoolSize,
                                          HystrixProperty<Integer> keepAliveTime, TimeUnit unit,
                                          BlockingQueue<Runnable> workQueue) {
    return this.delegate.getThreadPool(threadPoolKey, corePoolSize, maximumPoolSize,
        keepAliveTime, unit, workQueue);
  }

  @Override
  public ThreadPoolExecutor getThreadPool(HystrixThreadPoolKey threadPoolKey,
                                          HystrixThreadPoolProperties threadPoolProperties) {
    return this.delegate.getThreadPool(threadPoolKey, threadPoolProperties);
  }

  @Override
  public BlockingQueue<Runnable> getBlockingQueue(int maxQueueSize) {
    return this.delegate.getBlockingQueue(maxQueueSize);
  }

  @Override
  public <T> HystrixRequestVariable<T> getRequestVariable(
      HystrixRequestVariableLifecycle<T> rv) {
    return this.delegate.getRequestVariable(rv);
  }

  static class WrappedCallable<T> implements Callable<T> {

    private final Callable<T> target;
    private final RequestAttributes requestAttributes;

    public WrappedCallable(Callable<T> target, RequestAttributes requestAttributes) {
      this.target = target;
      this.requestAttributes = requestAttributes;
    }

    @Override
    public T call() throws Exception {
      try {
        RequestContextHolder.setRequestAttributes(requestAttributes);
        return target.call();
      }
      finally {
        RequestContextHolder.resetRequestAttributes();
      }
    }
  }

}
